APHIDID^ OF SOUTHERN CALIFORNIA VII 



E. O. I8SIG 

 HORTICULTURAL COMMISSIONER OF VENTURA COUNTY 



These descriptions and drawings were made from fresh specimens, either 

 living or immediately after they were killed. I did this in order to make the 

 color notes as complete and exact as possible and to get the exact shape and 

 proportions of each insect as it really ajjpears before being mounted. AH of the 

 drawings were made with a camera lucida and no pains were spared to make them 

 correct in the minutest detail. 



In determining these species I have sought freely the aid of the older workers 

 and best authorities on this group. I wish especially to acknowledge the valuable 

 help of Mr. J. T. Monell, Mr. John J. Davis, Prof. O. W. Oestlund and Prof. 

 W. M. Davidson and for their ready co-operation in every way. 



Aphis brassicae Linne 

 1735 Aphis brassicae Linn. Syst. Nat. 1, 2, p. 734.. 



CABBAGE LOUSE 



WINGED VIVIPAROUS FEMALE (Figure 1 69 A). 



Length of body 2.4 mm., width of mesothorax 0.7 mm., greatest width of 

 abdomen 0.95 mm., wing expansion 6.9 mm. 



Prevailing color — Dark greenish-yellow or brownish, slightly covered with 

 fine whitish powder. Head — Slightly wider than long, anterior portion darker 

 than the base, ventral surface greenish. Antennae — (Figure 169 H). Reaching just 

 beyond the middle of the abdomen — not quite to base of cornicles — dark, imbri- 

 cated, sparsely haired, length of articles: I, 0.07 mm.; II, 0.08 mm.; Ill, 0.6 

 mm.; IV, 0.25 mm.; V, 0.28 mm.; VI, 0.65 mm. (spur 0.5 mm.), total 1.93 mm. 

 Large number of circular sensoria on article III. Rostrum — Reaching to third 

 coxae, light with dark tip and base. Prothorax — Dark except narrow greenish 

 band at base. Mesothorax — Black. Metathorax — Amber with black basal band. 

 Abdomen — Dark green, yellowish brown or amber with dark transverse dorsal 

 markings and marginal spots, ventral surface distinctly segmented, evenly colored, 

 genital plate slightly dusky. Cornicles — (Figure 169 D). Cylindrical, slightly wider 

 just before tip, short, black, length 0.15 mm. Legs — Normal, dark amber brown, 

 coxEP dark ; femora with ajjical one-half darker ; tibia with base and apex darker ; 

 tarsi dusky at base and tip. Jf'ings — Hyaline, normal (see drawing). Primary — 

 Subcostal wide, amber; stigma long, narrow, length 0.8 mm., width 0.15 mm., 

 amber; veins amber brown. Style — Conical, as long or nearly as long, as cornicles, 

 light green or dusky, length 0.15 mm. 



APTEROUS VIVIPAROUS FEMALE (Figure 169 B and C). 



Length of body 2. mm., greatest width of body 1.2 mm., robust and nearly 

 globular in shape. 



